In order to pass tracking information for orders shipped using Amazon's carrier account, Shopify requires that the company name be included as part of the URL tracking template.
Shopify is saying the tracking_company can’t be null, it needs to be Amazon Logistics US or whatever the right carrier name is for each order.
There is some logic in Shopify that tries to figure out the carrier if tracking_company is not provided but it doesn’t seem to work for Amazon.
Created by Adam Lavergne